Hi All,

I noticed some intermittent issue under VirtualBox a long time ago back with 
FreeDOS 1.2. And, they still exists today with latest updates to v1.3. 

When you boot a default FreeDOS install in VirtualBox...

Using the default menu option #2. If it boots successfully, it seems to run for 
hours or days without an issue. I don’t think I ever see an issue when 
performing a clean boot from a VM Powered Off state (except maybe #4).
Using the emergency menu option #4. It usually boots. But, at some random 
period of time, the OS will become unresponsive with the cursor still blinking. 
Requiring a VM Reset or Power off. The VM equivalent to CTRL+ALT+DEL does not 
Using VM Menu to Reset, it will sometimes will lock up or crash during boot 
regardless of what menu choice. Sometimes, the VM will throw a OS crash 
message. Sometimes a JEMM error. Sometimes, but just freezes. It happens more 
frequently if a different boot option is selected on reboot.
Occasionally, it will even freeze (or sometimes crash with invalid opcode) 
while navigating the boot menu itself. 

My best guess is there are a couple compatibility issues going on. 

Without really digging into it, it appears that IF the VM boots successfully 
AND the normal drivers (HIMEMX, JEMM, FDAPM, CTMOUSE, UDVD2, SHSUCDX) are 
loaded, everything works fine. Even adding additional drivers like DOSLFN, it 
will remains stable once booted. I suspect it is something HIMEMX, JEMM or 
FDAPM is doing that prevents the random freezing that occurs with menu option 
#4 (no drivers). 

Also since it has crashed when just using the arrow keys to navigate the boot 
menu, there is possibly something going on in the kernel that VirtualBox does 
not like. 

This could all be Host OS specific. I generally use macOS and it is possible 
none of those issues happen under Windows or Linux. 

I really don’t have the time to try and figure it out beyond noticing the 
couple symptoms I have encountered. And, they don’t always happen. The most 
frequent is switching boot options on reboot. But, even that is intermittent. 

I just thought I would mention them in case anyone was interested or wanted to 
investigate further. Then we could submit a bug report in hopes of a fix to 
VirtualBox. But more likely, we would need to implement some patches to the 
kernel and/or other programs to avoid the problem(s).


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